[cillit bang]

For the attached question, once I see the answer it looks quite simple. But how do I know whether to use sin or cos and which number to put on top? (I'm in a bit of a hurry to go through all of the understanding properly I'm afraid) Thanks for any help! Pos rep given

[didgeridoo12uk]

whether you use cos or sine depends on which "sides of the triangle" you're using. you could use either in all questions or even tan if you feel like it

[Manitude]

It's just simple trig - SOH CAH TOA.

[Quexx]

I use tan instead... if you do the argument as: tanx = img/real, it gives the same answer and you don't have to worry about cos or sin.

For example the first one is:
tanx = 2/3
x = tan(-1)2/3
x = 0.588 radians

[cillit bang]

Thanks for your replies. Yeah, the only thing is the question doesn't mention which sides of the triangle these values are....so was just wondering how I know which one to use

[Brit_Miller]

(Original post by cillit bang)
Thanks for your replies. Yeah, the only thing is the question doesn't mention which sides of the triangle these values are....so was just wondering how I know which one to use

Horizontal axis is real, vertical axis is imaginary.